

Scott. — Resistance of Steel to Mechanical Shock. 525 



Captain Sankey, and the writer. The impact test adopted by- 

 Mr. Seaton consists in alloAving a tup of 61b. weight to fall 

 through 2 ft. on a notched specimen, of square section, \ in. side, 

 placed on a span of 3 in., the specimen being turned over after 

 each blow, its resistance to shock being measured by the num- 

 ber of blows required to produce fracture. The author has 

 designed and had constructed a machine for carrying out the 

 same test. This tester is illustrated by Fig. 7. 



The machine used by Captain Sankey is on the Charpy 

 principle as modified by Izod. A comparatively frictionless 

 pendulum with light rod and heavy bob is allowed to fall freely 



